ensure that the xp machine's firewall is either off or set to allow print sharing.
On each computer, bring up a command prompt (start->run->type "cmd.exe")
type net config workstation and make a note of the domain and computer name displayed.
if the domains listed do not match, you should make them match.
next type net view COMPUTERNAME (where computername = the name you found above) on the windows xp machine using the computer name of the xp machine, and ensure that the shared printer is listed.
if the domain listed for each machine is the same, type net view COMPUTERNAME on the laptop using the XP MACHINE's computer name and look for the printer share.
If the laptop can see the shares on the xp machine, add a new LOCAL printer with new local port int he form \\computername\printersharename where printersharename=printer share as listed in the net view computername step above